Drill bit



United States Patent DRILL BIT Edward B. Williams, Jr., Greenville, Tex.

Application May 3, 1954, Serial No. 427,006

4 Claims. (Cl. Z55- 72) This invention relates to a drill bit fordrilling earth formations and particularly a drill bit wherein thecutting elements are diamonds or the equivalent embedded into teeth ofthe bit. Such bits are particularly desirable fo-r drilling hard rockformations, however, when drilling certain types of hard rock,considerable vibration is setup in the drilling string. This vibrationis destructive of the bit and particularly the cutting elements thereof.

It is therefore a principal object of the present invention to eliminate-destructive vibration and provide a more efflcient and smootheroperation of such bits when drilling hard rocks by setting the diamondsto produce drag cuts.

Other objects of the invention are to provide a bit with a drag toothcontour to give the desired orientation of the cutting elements forproducing drag cuts in the formation, and to provide a diamond bit ofthis character specially adapted for core drilling.

In accomplishing these and other objects of the invention as hereinafterpointed out, l have provided improved structure the preferred form ofwhich is illustrated in the accompanying drawing wherein:

Fig. l is a perspective View of a core bit embodying the features of thepresent invention.

Fig. 2 is an enlarged fragmentary radial section through one tooth ofthe bit, the section being taken on the line 2--2 of Fig. 1.

Fig. 3 is an enlarged fragmentary section in the circumferentialdirection of the cutting face of the bit, the section being taken on theline 3 3 of Fig. 1.

Fig. 4 is a bottom plan view of one side of the drill bit.

Fig. 5 is a vertical section through the wall of the bit on the line 5 5of Fig. 4.

Referring more in detail to the drawings:

1 designates a drill bit of the core producing type and which embodiesthe features of the present invention, although the invention isadaptable to diamond bits of other types where a drag cutis desired.

The bit illustrated includes a substantially cylindrical sleeve-likebody 2 formed of suitable material and having a wall thickness towithstand drilling strains. The body 2 is shaped to provide an axialbore 3 extending inwardly from the drilling end 4 of the bit to connectwith a core barrel (not shown) and through which the core is passed aswill be well understood by those skilled in the drilling art. The upperend of the body 2 has a reduced exterior to form a shoulder 5 andprovide a threaded portion 6 to connect the bit with the core barrel,which in turn is connected with the lower end of a string of drill pipe(not shown). The drilling end 4 has inner and outer annular faces 7 and8 and an end drilling face 4'. The annular faces 7 and 8 project fromthe corresponding inner and outer faces 9 and 10 of the body portion 2to accommodate vertically extending grooves 11 that are spaced apartcircumferentially of the bit to provide water courses 12 for the innerface 7 of the bit and 13 for the outer face S as best shown in Fig. 1,the inner and outer grooves 11 being connected across the cutting face4' by radial grooves 14. The grooves 14 are arranged radially 2,818,233Patented Dec. 31, 1957 in a circular series and shaped to provide acircular series of radially extending teeth 15, each having an inclinedforward face 16 sloping upwardly in the rotational direction of the bitas indicated in Figs. 3 and 4 to join with a substantially vertical rearface 17 on the side of the next adjacent tooth as best shown in Fig. 3.The teeth thus extend transversely of the end portion of the cuttingface 4 and are of substantially triangular cross section in thecircumferential direction of the bit.

The cutting face 4 is rounded transversely between the inner and outerfaces 7 and 8 to provide `a circular cut having a rounded bottom. Theteeth 15 forming the cutting face 4 are provided with spaced apartgrooves 18 that extend in a generally circular direction and connect oneradial groove 14 with the adjacent groove 14. The grooves 18 cooperatein serving as circumferential water courses interconnecting the grooves14 and are of substantial V-shaped cross section. The sides of thegrooves 18 terminate in bevel faces 19 and 20 that converge at 21 asshown in Fig. 2. The grooves 18 are spaced apart a sufficient distanceto accommodate cutting elements 22 that are bedded in a row into thematerial of each tooth, for example in the manner disclosed in Patent2,371,488 for Core Bit, issued March 13, 1945. There need not be agroove between each of the adjacent cutting elements in the respectiveteeth.

Another method of securing the diamonds is to build up the teeth aboutthe diamonds by use of welding metal.

The cutting elements 22 are preferably diamonds', each having anelongated body provided with a cutting point or corner 23 at one end andhaving a 'cutting edge 24 extending from the cutting point along theside of the body in the direction of the opposite end of the diamond.The diamonds are oriented in the material of the teeth 15 with thecutting points exposed at the radial edges of the teeth and at thepoints 21 where the bevel faces 19 and 21 converge and the elongatedbodies of the diamonds are bedded within said teeth with the cuttingedges inclined upwardly and forwardly in corresponding relation with thcupwardly and forwardly sloping faces 16 of the teeth. It is thusapparent that the cutting portions of each diamond are set to produce acircumferential drag cut on the face of the formation as distinguishedfrom the gouge cut of the cutting elements disclosed in the abovenumbered patent. With this arrangement, the bit is effective in cuttinghard rock formations without vibration or chatter of the bit. It is alsoobvious that the upward slope of the faces 16 in the rotationaldirection of the bit gives ample clearance for passage of the drillingfluid as it passes from the inner vertical water courses to the outerwater courses of the bit to flush the cuttings from the path of thecutting elements.

The projecting faces 7 and 8 which extend circumferentially of the innerand outer sides of the bit may be provided with cutting elements 25 tomaintain the gauge of the bore hole and the size of the core. Thecutting elements 25 may also be diamonds bedded into the material of thebit in any suitable manner.

When in operation the bit is rotated by the drill pipe in the directionof the arrow (Fig. 1) so that the diamonds produce drag cuts in theformation. Simultaneously with rotation of the bit a drilling fluid iscirculated downwardly through the drill pipe, and around the corethrough the inner water courses 12 to wash the cuttings from the grooves14 and up the outer water courses to the top of the bore hole. Thedrilling uid also keeps the cutting surfaces of the bit in coolcondition and prevents heating of the diamonds.

I claim:

l. A drill bit including a cylindrical body member having a drilling endprovided with a circular cutting face extending about the axis of saidbody member for sup.

port on the bottom of the hole to be drilled by the bit when the bit isin use and rotated on said axis, said cutting face having a series ofteeth extending radially of said axis and eachhaving an upwardlyinclined forward face and a substantially vertical rear face relativelyto the direction that the bit is rotated, said faces converging to formradial edges, and cutting elements each having an elongated bodyprovided with a cutting point at one end and a cutting edge extendingfrom the cutting point along a side of said body in the direction of theopposite end, said elongated bodies being bedded'within said teeth withthe cutting points exposed at said radial edges and the cutting edgesinclined forwardly. and upwardly in corresponding relation with theinclined forward faces of the teeth to provide drag cuts by said cuttingelements when the bit is in use and turning about said axis.

2. A drill bit including a cylindrical body member having a drilling endprovided with a circular cutting face extending about the axis of saidbody member for support on the bottom of the hole to be drilled by thebit when the bit is in use and rotated on said axis, said cutting facehaving a series of teeth extending radially of said axis and each havingan upwardly inclined forward face and a substantially vertical rear facerelatively to the direction that the bit is rotated, said facesconverging to form radial edges, cutting elements each having anelongated body provided with a cutting point at one end and a cuttingedge extending from the cutting point along a side of said body in thedirection of the oppositeend, said elongated bodies being bedded withinsaid teeth with the cutting points exposed at said radial edges and the.

cutting edges inclined forwardly and upwardly in corresponding relationwith the inclined forward faces of the teeth to provide drag cuts bysaid cutting elements when the bit is in use and turning about saidaxis, and said teeth having grooves extending in a generally circulardirection with respect to the axis of the body member and locatedbetween the cutting elements.

3. A drill bit including a cylindrical body member having a drilling endprovided with a circular cutting face extending about the axisv of saidbody member for support on the bottom of the hole to be drilled by thebit when the bit is in use and rotated on said axis, said cutting facehaving a series of teeth extending radially of said axis and each havingforward faces inclined upwardly at an angle between 7 and 30 degrees andhaving a substantially vertical rear face relatively to the directionthat the bit is rotated, said faces converging to form radial edges, andcutting elements each having an elongated body provided with a cuttingpoint at one end and a cutting edge extending from the cutting pointalong a side of said body in the direction of the opposite end, saidelongated bodies being bedded within said teeth with the cutting pointsexposed at said radial edges and the cutting edges inclined forwardlyand upwardly in corresponding relation With the inclinedlforward facesof the teeth to provide drag cuts by said cutting elements when the bitis in use and turning aboutfsaid axis.

4. A -core bit including a body member having a cylindrical wallencircling a core opening in the axis of said body member `and having anend providing a circular cutting face for-support on the bottom ofa-hole to be drilled when the bit is in use and rotated on said axis,said circular cutting face curving into inner and outer annular faces ofthe cylindrical wall and having a series of cutting teeth each having aninclined forward face and a substantially vertical rear face relativelyto the direction that the bit is rotated, said faces converging to formedges for said teeth, cutting elements, each having an elongatedV bodyprovidedv with a :cutting point at one end and a cutting edge extendingfrom the cutting point along a side of said elongated body in theydirection of the opposite end, said elongated bodies being beddedwithin said teeth with the cutting points exposed at said edges of theteeth and they cutting edges inclined forwardly in correspondingrelation with the inclined forward faces of the teeth to provide dragcuts by said cutting elements when the bit is in use and turning aboutsaid axis, and cutting elements bedded in said inner and outer annularface portions.

References Cited in the le of this patent UNITED STATES PATENTS2,136,359 Bley et al Nov. 15, 19384 2,371,488 Williams Mar. 13, 19452,495,400 Williams Jan. 24, 1950 2,593,229 Wallace Apr. 15, 1952

